Sintering and Phase Evolution of Electroless‐Nickel‐Coated Alumina Powder

Abstract

Alumina-nickel powders have been prepared via electroless-nickel (EN) coating of submicrometer-sized alumina powder. The EN layers contain 5.1 ؎ 0.4 wt% phosphorus and are very unevenly distributed on the surfaces of the alumina particles. These layers consist of amorphous and microcrystalline phases. At temperatures ≥1300°C, the EN layers de-wet from the alumina surfaces to become discrete, round particles in the alumina matrix. The alumina-EN pellets can be sintered to reach ∼95% of the theoretical density at 1500°C for 4 h in graphite crucibles. The phases of the sintered samples consist of alumina, nickel, and nickel phosphides. However, in the exterior region of the sample sintered at 1500°C for 4 h, Ni 3 Al will also form.

Synthesis of nickel coatings with high surface area on the ceramic powders

“…Powder composites are interesting as building blocks for creation of new electrodes of chemical current sources based on them [8][9][10]. The presence of such a wide range of applications of nickel-alumina materials requires the development of existing methods of their synthesis [11][12][13][14][15][16][17].…”